nure.
We should have expected a greater increase from such a liberal dressing
of barn-yard manure. I think the explanation is this: The manure had not
been piled. It was probably taken out fresh from the yard (this, at any
rate, was the case when I was at Rothamsted), and plowed under late in
the season. And on this heavy land, manure will lie buried in the soil
for months, or, if undisturbed, for years, without decomposition. In
other words, while this 14 tons of barn-yard manure, contained at least
150 lbs. of nitrogen, and a large quantity of minerals and carbonaceous
matter, it did not produce a bushel per acre more than a manure
containing less than 12 lbs. of nitrogen. And on plot 19, a manure
containing less than 15 lbs. of available nitrogen, produced nearly 4
bushels per acre more wheat than the barn-yard manure containing at
least _ten times_ as much nitrogen.
There can be but one explanation of this fact. The nitrogen in the
manure lay dormant in this heavy soil. Had it been a light sandy soil,
it would have decomposed more rapidly and produced a better effect.
As we have before stated, John Johnston finds, on his clay-land, a far
greater effect from manure spread on the surface, where it decomposes
rapidly, than when the manure is plowed under.
The Deacon was looking at the figures in the table, and not paying much
attention to our talk. "What could a man be thinking about," he said,
"to burn 14 tons of good manure! It was a great waste, and I am glad the
ashes did no sort of good."
After the wheat was harvested in 1844, the land was immediately plowed,
harrowed, etc.; and in a few weeks was plowed again and sown to wheat,
the different plots being kept separate, as before.
The following table shows the manures used this second year, and the
yield per acre:
Experiments at Rothamsted on the Growth of Wheat, Year After Year,
on The Same Land.
Table II.--Manures and Produce; 2nd Season, 1845. Manures and Seed
(Old Red Lammas) Sown March 1845.
Manures:
FM Farmyard Manure.
SiP Silicate of Potass.[1]
PhP Phosphate of Potass.[2]
SPL Superphosphate of Lime.[2]
B-A Bone-ash.
MAc Muriatic Acid.
G Guano.
SAm Sulphate of Ammonia.
MAm Muriate of Ammonia.
CAm Carbonate of Ammonia.
RC Rape Cake.
T Tapioca.
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